El Basiony N M, Elgendy Amr, Nady H, Migahed M A, Zaki E G
Egyptian Petroleum Research Institute (EPRI) Nasr City Cairo Egypt
Chemistry Department, Faculty of Science, Fayoum University Egypt.
RSC Adv. 2019 Apr 4;9(19):10473-10485. doi: 10.1039/c9ra00397e. eCollection 2019 Apr 3.
In this work, we report the synthesis of two Schiff bases of substituted gallic acid derivatives amidation reaction and their characterization using H-NMR spectroscopy to study their inhibition performance on the aggressive attack of HCl on mild steel (MS). The inhibitive performance was examined using chemical (weight loss) and electrochemical (Tafel and EIS) test methods. The results indicate that these derivatives significantly suppress the dissolution rate of mild steel adsorption phenomena, which correlates to the Langmuir adsorption model. Tafel data display the mixed-type properties of these compounds and EIS results show that increasing Schiff base concentration not only leads to delaying the charge transfer ( ) of iron from 26.4 ohm cm to 227.7 ohm cm but also decreases the capacitance of the adsorbed double layer ( ) from 8.58 (F cm) × 10 to 2.55 (F cm) × 10. The inhibition efficiency percentage reaches the peak (90%) at optimum concentration of 250 ppm. The Monte Carlo simulations confirm the adsorption ability of the as-prepared compounds on the Fe (1 1 0) crystal. The SEM/EDX results revealed the presence of a protective film on the mild steel sample.
在这项工作中，我们报道了通过酰胺化反应合成两种取代没食子酸衍生物席夫碱，并使用氢核磁共振光谱对其进行表征，以研究它们对盐酸侵蚀低碳钢（MS）的抑制性能。使用化学（失重）和电化学（塔菲尔和电化学阻抗谱）测试方法检测抑制性能。结果表明，这些衍生物通过吸附现象显著抑制低碳钢的溶解速率，这与朗缪尔吸附模型相关。塔菲尔数据显示这些化合物具有混合型特性，电化学阻抗谱结果表明，增加席夫碱浓度不仅会使铁的电荷转移电阻（）从26.4Ω·cm增加到227.7Ω·cm，还会使吸附双层电容（）从8.58（F/cm）×10⁻⁶降低到2.55（F/cm）×10⁻⁶。在250ppm的最佳浓度下，抑制效率百分比达到峰值（90%）。蒙特卡罗模拟证实了所制备化合物在Fe(1 1 0)晶体上的吸附能力。扫描电子显微镜/能谱分析结果显示低碳钢样品上存在保护膜。
